New progress in micromechanics-based CDM models and their application to CMCs

A previously developed continuum-damage theory for modeling ceramic-matrix composites is modified relative to the deactivation rule. The new deactivat ion is directly based on mechanics of microcrack behaviour, considering bot h closure effects and the corresponding elastic energy storage. The model u ses two sets of damage state variables, scalar ones corresponding to microc racks oriented by reinforcements and a second rank tensor that evolves with the maximum principal strain directions. The model is applied to uniaxial and multiaxial monotonic and cyclic tests on a SiC/SiC composite. (C) 2001 Elsevier Science Ltd. All rights reserved.